JP2010203543A - Rotary actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary actuator which is easy to attach to a shift range switching device and is capable of switching the shift range at high precision. <P>SOLUTION: The rotary actuator 10 is provided with an electric motor 3, a housing 2 which accommodates the electric motor 3, an output shaft 5 which is rotatably supported by the housing 2 and is capable of being coupled with a manual shaft so as to transmit rotating output of the electric motor 3 to the manual shaft of a shift range switching device and an urging means 6 capable of urging the output shaft 5 to a forward or reverse direction in the rotating direction. The urging means 6 urges the output shaft 5 to the reverse direction when the output shaft 5 is in a position which is rotated on the forward direction side rather than a reference position if a predetermined position of rotating direction of the output shaft 5 relative to the housing 2 is assumed as the reference position. On the other hand, the urging means 6 urges the output shaft 5 to the forward direction when the output shaft 5 is in a position which is rotated on reverse direction side rather than the reference position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a rotary actuator that drives a shift range switching device.

  2. Description of the Related Art Conventionally, in an automobile shift range switching device, a shift range selected by a driver is detected by an electronic control device (hereinafter referred to as “ECU”), and a rotary actuator is driven and controlled in accordance with the detected value, thereby automatically shifting. A shift-by-wire system for switching the shift range of a machine is known (see Patent Document 1). The shift range switching device has a manual shaft that is rotatably supported. The rotary actuator switches the shift range of the automatic transmission by rotationally driving the manual shaft.

  Incidentally, the rotary actuator is generally attached to the shift range switching device in a state where the output shaft and the manual shaft are coupled by spline fitting. For this reason, backlash occurs in the rotational direction between the output shaft and the manual shaft, and there is a possibility that the rotational angles of the both may be shifted by this backlash amount. This deviation hinders high-precision manual shaft control by the rotary actuator. Therefore, in order to close the backlash, for example, it is conceivable to install a torsion coil spring around the output shaft and urge the output shaft in one rotational direction (not a well-known technique).

  As described above, in the case of a rotary actuator that urges the output shaft in one rotational direction, the output shaft is fully rotated in one rotational direction before being attached to the shift range switching device. is there. Therefore, after the output shaft in this state is spline-fitted to the manual shaft, to attach the rotary actuator to a predetermined mounting location of the shift range switching device with a bolt or the like, the main body of the rotary actuator matches the mounting location. Need to be rotated. However, when the amount of rotation is large, the rotary actuator may interfere with other surrounding members and the like, and it may be difficult or impossible to rotate the main body of the rotary actuator.

JP 2005-265151 A

  An object of the present invention is to provide a rotary actuator that can be easily attached to a shift range switching device and can switch the shift range with high accuracy.

  The invention according to claim 1 is a rotary actuator attached to a shift range switching device that switches a shift range of an automatic transmission. The shift range switching device has a manual shaft that is rotatably supported, and the shift range is switched when the manual shaft is rotationally driven by a rotary actuator. The present invention includes an electric motor, a housing that houses the electric motor, an output shaft that is rotatably supported by the housing and that can be coupled to the manual shaft so as to transmit the rotational output of the electric motor to the manual shaft, and the output shaft in the rotational direction. Biasing means capable of biasing in the direction or the reverse direction.

  Then, assuming that a predetermined position in the rotation direction of the output shaft relative to the housing is a reference position, the urging means applies the output shaft in the reverse direction when the output shaft is at a position rotated in the forward direction from the reference position. Rush. On the other hand, the urging means urges the output shaft in the forward direction when the output shaft is at a position rotated to the opposite side of the reference position. That is, when the output shaft is at a position different from the reference position, the output shaft is always urged in the forward direction or the reverse direction by the urging means. Thereby, even if the output shaft and the manual shaft are coupled with a predetermined play, it is possible to close the backlash in the rotational direction generated between the output shaft and the manual shaft. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator.

  In the rotary actuator according to the present invention, the output shaft is stationary at the reference position by the action of the urging means before being attached to the shift range switching device. Usually, the rotary actuator is attached to the shift range switching device in a state where the manual shaft is at a specific position (for example, a position corresponding to the N range of the automatic transmission). Therefore, for example, “the reference position of the output shaft in a state in which the rotary actuator is attached to the shift range switching device is specified among a plurality of positions in the rotation direction of the manual shaft corresponding to each shift range of the automatic transmission. `` Set to correspond to the vicinity of the position '' and `` Set the specific position as the position in the rotation direction of the manual shaft relative to the shift range switching device when the rotary actuator is attached to the shift range switching device ''. For example, when attaching a rotary actuator whose output shaft is stationary at the reference position to the shift range switching device, after coupling the output shaft to the manual shaft, the body of the rotary actuator is resisted against the biasing force of the biasing means. Just by rotating it slightly, it can be matched with the mounting location of the shift range switching device. Kill. As a result, even when other members or protrusions from the shift range switching device are located around the rotary actuator, the main body of the rotary actuator interferes with other members or protrusions during rotation during mounting. Is reduced. Therefore, it becomes easy to attach the rotary actuator to the shift range switching device.

  In the invention according to claim 2, when the reference position is attached to the shift range switching device with the output shaft coupled to the manual shaft, the rotation direction of the manual shaft corresponding to each shift range of the automatic transmission Corresponding to a position between two specific positions adjacent to each other. Therefore, when the rotary actuator is attached to the shift range switching device, the output shaft is moved forward or backward in the rotational direction by the biasing means regardless of the shift range corresponding to the manual shaft. It will always be energized. As a result, even if the output shaft and the manual shaft are coupled with a predetermined play, when the manual shaft is in a position corresponding to each shift range of the automatic transmission, the output shaft and the manual shaft are not connected. The play in the direction of rotation that occurs can be packed. As a result, a shift between each shift range of the automatic transmission and the rotation angle of the output shaft that should correspond to each of the shift ranges can be suppressed. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator.

  In the present invention, for example, if any one of the two adjacent positions is set as the position of the manual shaft when the rotary actuator is attached to the shift range switching device, the output shaft is the reference position. When mounting a rotary actuator that is stationary in the shift range switching device, after connecting the output shaft to the manual shaft, the body of the rotary actuator can be rotated slightly against the biasing force of the biasing means. It is possible to match the mounting location of the shift range switching device. Therefore, it becomes easy to attach the rotary actuator to the shift range switching device.

  In the invention according to claim 3, the urging means includes a shaft member fixed to the housing on the outer diameter side of the output shaft, an external tooth member provided on the outer wall in the radially outer direction of the output shaft, and rotating with the output shaft. A rotating member that has external teeth meshing with the external tooth member and is supported so as to be rotatable about the axis of the shaft member, and an urging force that can urge the rotating member in the forward direction or the reverse direction in the rotational direction. It consists of members. The biasing member can bias the output shaft in the forward direction or the reverse direction in the rotational direction via the rotating member. In the present invention, the biasing means is located outside the diameter of the output shaft. Therefore, for example, an increase in the size of the rotary actuator in the axial direction can be suppressed as compared with the case where the urging means is arranged on the axial direction side of the output shaft. Moreover, according to the said structure of this invention, there can exist an effect similar to the effect of the invention of Claim 1 and 2 mentioned above.

  According to a fourth aspect of the present invention, the housing has a housing-side protrusion that protrudes in the axial direction of the shaft member. The rotating member has a rotating member side protrusion that protrudes in the axial direction of the shaft member. The urging member is provided on the rotating member such that the housing side protruding portion and the rotating member side protruding portion are sandwiched between one end and the other end. In addition, when the output shaft is in a position rotated to the positive direction side from the reference position, one end or the other end of the biasing member is locked to the housing side protruding portion, and the other end of the one end or the other end rotates. Locked by the moving member-side protrusion, the output shaft is biased in the reverse direction via the rotating member. On the other hand, when the output shaft is at a position rotated in the direction opposite to the reference position, the urging member has one end or the other end locked to the housing-side protruding portion and one end or the other end rotated. Locked by the moving member-side protrusion, the output shaft is urged in the forward direction via the rotating member. According to the said structure of this invention, there can exist an effect similar to the effect of the invention of Claim 1, 2 and 3 mentioned above.

  The invention according to claim 5 further includes a shift position sensor capable of detecting a shift range of the automatic transmission by detecting a relative rotation angle between the rotation member and the fixed member fixed to the housing. ing. The rotating member rotates in conjunction with the rotation of the output shaft, and the manual shaft also rotates in conjunction with the rotation of the output shaft. That is, the rotating member and the manual shaft are linked via the output shaft. Therefore, the shift position sensor can detect the position in the rotation direction of the manual shaft corresponding to the rotation angle, that is, the shift range of the automatic transmission, by detecting the rotation angle of the rotation member.

  Since the rotating member and the manual shaft are linked via the output shaft, the backlash in the rotational direction between the rotating member and the output shaft and the backlash in the rotational direction between the output shaft and the manual shaft are the shift position sensors. May cause an error in the detection of the shift range. However, in the present invention, the biasing member can bias the output shaft in the forward direction or the reverse direction in the rotational direction via the rotating member. Thereby, in addition to the play between the output shaft and the manual shaft, the play between the rotating member and the output shaft can also be packed. Therefore, an error between the detection value detected by the shift position sensor and the actual shift range can be reduced. As a result, the shift range of the automatic transmission can be detected with high accuracy by the shift position sensor. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator.

  When the rotary actuator is attached to the shift range switching device and the output shaft is at the reference position, the biasing force applied from the biasing member to the output shaft is “0”. Therefore, at this time, backlash occurs between the rotating member and the output shaft, and between the output shaft and the manual shaft, and an error may occur in the shift range of the automatic transmission detected by the shift position sensor. However, the output shaft is coupled to the manual shaft so that the reference position corresponds between two specific positions adjacent to each other in the rotational direction of the manual shaft corresponding to each shift range of the automatic transmission. If so, in a state where the manual shaft is in a position corresponding to one of the shift ranges of the automatic transmission, the output shaft is always urged in the forward direction or the reverse direction in the rotational direction by the urging member. As a result, the play between the rotating member and the output shaft and between the output shaft and the manual shaft is in a packed state. Therefore, the occurrence of an error in the shift range of the automatic transmission detected by the shift position sensor is reduced.

  In the present invention, since the rotation member is located on the outer side of the output shaft, the shift position sensor can be arranged on the outer side of the output shaft. Thereby, compared with the case where a shift position sensor is arrange | positioned, for example to the axial direction side of an output shaft, the increase in the physique of the axial direction of a rotary actuator or the deterioration of the mounting property of a rotary actuator can be suppressed.

  In the invention described in claim 6, the output shaft can be coupled to the manual shaft of the shift range switching device by spline fitting. When the rotary actuator according to the present invention is attached to the shift range switching device in a state where the output shaft and the manual shaft are coupled by spline fitting, there is a backlash in the rotational direction between the output shaft and the manual shaft. It becomes easy. However, in the present invention, the output shaft is urged in the forward or reverse direction in the rotational direction by the urging means. As a result, even if there is a backlash between the output shaft and the manual shaft, this backlash can be reduced. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator.

Sectional drawing which shows the rotary actuator by one Embodiment of this invention. Schematic which shows the shift-by-wire system to which the rotary actuator by one Embodiment of this invention is applied. The figure which looked at the output shaft and the rotation member from the arrow X direction of FIG. FIGS. 2A and 2B are views of the output shaft and the rotating member as viewed from the direction of the arrow X in FIG. 1, where FIG. 1A is a view when the output shaft is rotated to the positive side from the reference position, and FIG. The figure when it exists in the position which the axis | shaft rotated in the reverse direction side rather than the reference position. It is a figure which shows the relationship between the rotation angle of an output shaft, and the urging | biasing force which an output shaft receives, (A) is a figure which shows the urging | biasing force which the output shaft of the rotary actuator by one Embodiment of this invention receives, (B) FIG. 4 is a diagram illustrating an urging force received by an output shaft of a rotary actuator according to a comparative example. The figure which shows the relationship between the rotation angle of a manual shaft, and the voltage output from the shift position sensor of the rotary actuator by one Embodiment of this invention.

Hereinafter, a rotary actuator according to the present invention will be described with reference to the drawings.
(One embodiment)
1 and 2 show an embodiment in which the present invention is applied to a rotary actuator attached to a shift range switching device of an automatic transmission of an automobile. The rotary actuator 10 is used to drive the shift range switching device 100 in a shift-by-wire system. The shift range switching device 100 switches the shift range of the automatic transmission when the manual shaft 101 is rotationally driven by the rotary actuator 10. The rotation of the rotary actuator 10 is controlled by an electronic control unit (ECU) 11. The rotary actuator 10 is attached to the shift range switching device 100 as shown in FIG. First, the shift range switching device 100 will be described below.

The shift range switching device 100 includes a shift range switching mechanism 110 and a parking switching mechanism 120.
The shift range switching mechanism 110 includes a manual shaft 101, a detent plate 102, a hydraulic valve body 104, and the like. One end of the manual shaft 101 is splined to the output shaft 5 of the rotary actuator 10 (described later). The detent plate 102 is formed in a fan shape extending radially outward from the manual shaft 101 and rotates integrally with the manual shaft 101. The detent plate 102 is provided with a pin 103 that protrudes in parallel with the manual shaft 101. The pin 103 is locked to an end portion of a manual spool valve 105 provided in the hydraulic valve body 104. For this reason, the manual spool valve 105 is reciprocated in the axial direction by the detent plate 102 that rotates integrally with the manual shaft 101. The manual spool valve 105 reciprocates in the axial direction to switch a hydraulic pressure supply path to a hydraulic clutch of an automatic transmission (not shown). As a result, the engagement state of the hydraulic clutch is switched, and the shift range of the automatic transmission is changed.

  The detent plate 102 has a concave portion 151, a concave portion 152, a concave portion 153, and a concave portion 154 at an end portion in the radial direction. The concave portions 151 to 154 correspond to, for example, a P range, an R range, an N range, and a D range, which are shift ranges of an automatic transmission (not shown). The stopper 107 supported at the tip of the leaf spring 106 is engaged with any one of the recesses 151 to 154 of the detent plate 102, whereby the position of the manual spool valve 105 in the axial direction is determined.

When a rotational force is applied to the detent plate 102 from the rotary actuator 10 via the manual shaft 101, the stopper 107 moves to another adjacent recess (any one of the recesses 151 to 154). As a result, the axial position of the manual spool valve 105 changes.
For example, when the manual shaft 101 is rotated clockwise as viewed in the direction of arrow Y in FIG. 2, the pin 103 pushes the manual spool valve 105 into the hydraulic valve body 104 via the detent plate 102, and the hydraulic valve body 104 The inner oil passage is switched in the order of D, N, R, and P. Thereby, the shift range of the automatic transmission is switched in the order of D, N, R, and P.

On the other hand, when the manual shaft 101 is rotated counterclockwise, the pin 103 pulls out the manual spool valve 105 from the hydraulic valve body 104, and the oil passage in the hydraulic valve body 104 is switched in the order of P, R, N, and D. . Thereby, the shift range of the automatic transmission is switched in the order of P, R, N, and D.
As described above, the rotation angle of the manual shaft 101 driven to rotate by the rotary actuator 10, that is, a predetermined position in the rotation direction, corresponds to each shift range of the automatic transmission.

  The parking switching mechanism 120 includes a park rod 121, a park pole 123, a parking gear 126, and the like. The park rod 121 is formed in a substantially L shape, and the detent plate 102 is connected to one end thereof. A conical portion 122 is provided at the other end of the park rod 121. When the park rod 121 converts the rotational movement of the detent plate 102 into a linear movement, the conical part 122 reciprocates in the axial direction. The park pole 123 is in contact with the side surface of the conical portion 122. Therefore, when the park rod 121 reciprocates, the park pole 123 is driven to rotate about the shaft portion 124. A protrusion 125 is provided in the rotation direction of the park pole 123. When the protrusion 125 meshes with the gear of the parking gear 126, the rotation of the parking gear 126 is restricted. As a result, the driving wheel is locked via a drive shaft or a differential gear (not shown). On the other hand, when the projection 125 of the park pole 123 is disengaged from the gear of the parking gear 126, the parking gear 126 becomes rotatable and the lock of the driving wheel is released.

Next, the rotary actuator 10 will be described.
As shown in FIG. 1, the rotary actuator 10 includes a housing 2, an electric motor 3, a speed reducer 4, an output shaft 5, an urging means 6, and the like. The rotary actuator 10 is a servo motor that drives the shift range switching mechanism 110 of the shift range switching device 100.

  The speed reducer 4 decelerates the rotational output of the electric motor 3 and transmits it to the shift range switching mechanism 110 of the shift range switching device 100 via the output shaft 5. The rotation of the electric motor 3 is controlled by the ECU 11 connected to the rotary actuator 10 (see FIG. 2). That is, the shift range switching device 100 controls the shift range switching mechanism 110 and the parking switching mechanism 120 by controlling the rotation direction, rotation speed, rotation angle, and the like of the electric motor 3 by the ECU 11.

  The housing 2 includes a front housing 21 and a rear housing 22. In the present embodiment, the front housing 21 is made of metal, and the rear housing 22 is made of resin. The front housing 21 and the rear housing 22 are fixed by bolts 23. An electric motor 3 and a speed reducer 4 are accommodated in an internal space of the housing 2 formed by the front housing 21 and the rear housing 22.

  The electric motor 3 is a brushless SR motor (switched reluctance motor) that generates a driving force without using a permanent magnet. The electric motor 3 includes a stator 31 and a rotor 35. The stator 31 is formed in a substantially annular shape, and is fixed to the rear housing 22 in a non-rotatable manner by being press-fitted into a metal fixing plate 24 that is insert-molded in the rear housing 22.

  The stator 31 includes a stator core 32 and a coil 33. The stator core 32 is formed by laminating a plurality of thin metal plates in the thickness direction. The stator core 32 is provided with a plurality of stator teeth projecting at predetermined angles (for example, every 30 degrees) in the radially inward direction. Each of the stator teeth is provided with a coil 33 that generates a magnetic force in the stator teeth. The coil 33 is energized and controlled by the ECU 11.

  The rotor 35 is provided on the inner diameter side of the stator 31. The rotor 35 includes a rotor shaft 36 and a rotor core 37. The rotor shaft 36 is rotatably supported at one end by the front bearing 12 and at the other end by the rear bearing 13. Thereby, the rotor 35 can rotate relative to the housing 2 and the stator 31.

  The front bearing 12 is fitted and fixed to the inner periphery of the output shaft 5 of the speed reducer 4 described later. The output shaft 5 is rotatably supported by a metal bearing 14 provided on the inner periphery of the front housing 21. That is, one end of the rotor shaft 36 is rotatably supported by the front housing 21 via the front bearing 12, the output shaft 5, and the metal bearing 14. The other end of the rotor shaft 36 is rotatably supported by a rear bearing 13 that is press-fitted and fixed to the fixed plate 24 of the rear housing 22.

The rotor core 37 is formed by laminating a plurality of metal thin plates in the plate thickness direction, and is press-fitted and fixed to the rotor shaft 36. The rotor core 37 is provided with a plurality of rotor teeth projecting at predetermined angles (for example, every 45 degrees) toward the stator core 32 on the outer diameter side.
When the energization position and energization direction of each coil 33 are sequentially switched based on the drive signal output from the ECU 11, the stator teeth that magnetically attract the rotor teeth are sequentially switched, and the rotor 35 rotates to one or the other. Thus, by switching the energization to each coil 33 and controlling the magnetic force generated in each coil 33, the rotor 35 can be rotated in an arbitrary direction.

The reduction gear 4 includes a sun gear 41, a ring gear 42, an output shaft 5, and the like. The reduction gear 4 is a kind of so-called planetary gear device. The rotor shaft 36 described above has an eccentric portion 38 on the output shaft 5 side in the axial direction of the rotor core 37. The eccentric portion 38 rotates eccentrically with respect to the rotation center of the rotor shaft 36.
The sun gear 41 is formed in a substantially disk shape. The sun gear 41 is supported by the eccentric portion 38 via the bearing 15 so as to be relatively rotatable. Therefore, the sun gear 41 rotates eccentrically with respect to the rotor shaft 36. The sun gear 41 has external teeth on the outer periphery.

  The ring gear 42 is formed in a substantially annular shape. The ring gear 42 is press-fitted and fixed to the front housing 21. The ring gear 42 has inner teeth that can mesh with the outer teeth of the sun gear 41 on the inner periphery. Thereby, when the sun gear 41 rotates eccentrically with respect to the rotor shaft 36, the outer teeth of the sun gear 41 are sequentially meshed with the inner teeth of the ring gear 42 to rotate in the direction opposite to the rotation direction of the rotor shaft 36. Depending on the number of teeth of the sun gear 41 and the ring gear 42, the rotation speed of the sun gear 41 is obtained by reducing the rotation speed of the rotor shaft 36 to 1/60, for example.

  The output shaft 5 has a substantially annular flange 51 positioned on the side of the sun gear 41 opposite to the rotor core 37. The flange 51 is formed with a plurality of pin holes 52 on the same circumference. The sun gear 41 is formed with a plurality of pins 43 protruding toward the flange 51 side. The plurality of pins 43 are loosely fitted in the pin holes 52 of the output shaft 5. When the sun gear 41 rotates, power is transmitted from the pin 43 to the inner wall of the pin hole 52 of the output shaft 5. Thereby, the rotation component of the sun gear 41 is transmitted to the output shaft 5.

  The output shaft 5 can be coupled to the manual shaft 101 so as to transmit the rotation output of the electric motor 3 to the manual shaft 101 of the shift range switching device 100. Specifically, a coupling hole 53 into which the manual shaft 101 can be inserted is formed at the end of the output shaft 5 opposite to the flange 51. A plurality of spline grooves 54 extending in the axial direction are formed on the inner wall of the coupling hole 53 of the output shaft 5. On the other hand, a plurality of spline teeth that can be fitted in the spline groove 54 are formed on the outer wall of the end portion of the manual shaft 101. Therefore, if the output shaft 5 and the manual shaft 101 are connected by inserting the manual shaft 101 into the coupling hole 53, the output shaft 5 and the manual shaft 101 are coupled by spline fitting. Thereby, the rotary actuator 10 can rotationally drive the manual shaft 101 of the shift range switching device 100.

  In the rotary actuator 10 described above, the encoder 16 is mounted on the rotor core 37 side of the rear housing 22. The encoder 16 includes a magnet 17 that rotates integrally with the rotor 35, and a magnetic detection Hall IC 18 that is disposed to face the magnet 17 in the rear housing 22 and detects passage of the magnetic flux generation unit in the magnet 17. The Hall IC 18 is supported by a substrate 19 fixed to the rear housing 22. The Hall IC 18 is, for example, a rotation angle detection Hall IC that detects a magnetic flux of multipolar magnetization of the magnet 17, an index signal Hall IC that detects a magnetic flux generated every time the phases of the coils 33 are energized, and the like. Consists of. With the above configuration, the encoder 16 can detect the rotation angle of the rotor 35. By detecting the rotation angle of the rotor 35 with the encoder 16, the electric motor 3 can be operated at high speed without being stepped out.

  The ECU 11 that controls energization of the motor 3 includes a CPU that performs control processing, arithmetic processing, and the like, storage means (ROM, RAM, SRAM, EEPROM, etc.) that stores various programs and data, an input circuit, an output circuit, a power supply circuit, and the like. It is equipped with a configured microcomputer. The ECU 11 performs energization control of each coil 33 based on the calculation result.

  The ECU 11 includes a “normal control unit” that controls the electric motor 3 so that a shift range operating unit (not shown) operated by the occupant and a shift range position recognized by the ECU 11 coincide with each other, and the rotational speed of the rotor 35 from the output of the encoder 16. Various control programs such as “rotor reading means” for grasping the rotation speed and rotation angle are stored.

Next, the biasing means 6 will be described.
As shown in FIG. 3, the urging means 6 includes a shaft member 61, an external tooth member 62, a rotating member 63, an urging member 64, and the like.
The shaft member 61 is formed, for example, in a substantially cylindrical shape from metal. The shaft member 61 is provided outside the diameter of the output shaft 5 so that the shaft is substantially parallel to the shaft of the output shaft 5. One end of the shaft member 61 is press-fitted and fixed to the front housing 21. Thereby, the shaft member 61 is not rotatable relative to the front housing 21.

The external tooth member 62 is formed in a substantially annular shape from metal, for example. The external tooth member 62 is fitted to the outer wall of the output shaft 5 in the radially outward direction. Thereby, the external tooth member 62 rotates together with the output shaft 5. The external tooth member 62 has external teeth 621 on the outer peripheral edge.
The rotating member 63 is made of, for example, resin. The rotating member 63 includes a substantially cylindrical tube portion 631, and an annular portion 632 that is formed to extend from one end portion of the tube portion 631 in a substantially annular shape in a radially outward direction. The rotating member 63 has external teeth 633 that mesh with the external teeth 621 of the external tooth member 62 at a part of the outer peripheral edge of the annular portion 632. A bearing 634 is provided between the inner wall of the cylindrical portion 631 and the outer wall of the other end portion of the shaft member 61. Thereby, the rotation member 63 is rotatably supported by the shaft member 61 via the bearing 634.

The biasing member 64 is a kind of torsion coil spring. The urging member 64 is formed, for example, by winding a wire made of metal in a coil shape, and both end portions (end portion 641 and end portion 642) are bent toward the radially outer side.
The front housing 21 has a housing side protruding portion 25 formed to protrude in the axial direction of the shaft member 61. Moreover, the rotation member 63 has the rotation member side protrusion part 635 formed so that it may protrude in the axial direction of the shaft member 61 from the annular part 632 (refer FIG. 1). The rotation member side protrusion 635 is formed on the opposite side of the external teeth 633 with the shaft member 61 interposed therebetween. Note that a gap 636 having a width slightly larger than the width of the wire forming the biasing member 64 is formed between the rotating member-side protruding portion 635 and the cylindrical portion 631.

  The urging member 64 is disposed on the outer periphery of the cylindrical portion 631, and is provided on the rotating member 63 so that the housing side protruding portion 25 and the rotating member side protruding portion 635 are sandwiched between the end portions 641 and 642. It has been. The urging member 64 is provided on the rotating member 63 in a state where a part of the circumferential direction enters the gap 636. Therefore, the position of the urging member 64 is stabilized with respect to the rotation member 63 and the drop-off from the rotation member 63 is suppressed.

  Here, when the output shaft 5 is in the position shown in FIG. 3, that is, the housing side protruding portion 25 and the rotating member side protruding portion 635 are on a straight line L passing through the axis of the output shaft 5 and the axis of the shaft member 61. The position in the rotational direction of the output shaft 5 with respect to the front housing 21 is referred to as a “reference position”. For the following explanation, in FIG. 3, one point on the output shaft 5 that overlaps the straight line L is d1, and the clockwise direction toward the page with respect to the rotation direction of the output shaft 5 is the “positive direction”, and the counterclockwise direction. The direction of rotation is the “reverse direction”. The “positive direction” corresponds to the clockwise direction when viewed from the arrow X direction in FIG. 1, and the counterclockwise direction when viewed from the arrow Y direction in FIG. Further, the “reverse direction” corresponds to the counterclockwise direction when viewed from the arrow X direction in FIG. 1 and the clockwise direction when viewed from the arrow Y direction in FIG.

  As described above, the rotating member 63 has the external teeth 633 that mesh with the external teeth 621 of the external tooth member 62 provided on the output shaft 5. Therefore, as shown in FIG. 4A, when the output shaft 5 rotates in the forward direction from the reference position so that the point d1 on the output shaft 5 is away from the straight line L, the rotating member 63 It rotates counterclockwise around the axis. When the rotating member 63 rotates counterclockwise, the end portion 642 of the biasing member 64 is locked to the housing side protruding portion 25, and the end portion 641 is locked to the rotating member side protruding portion 635. Yes. In this state, the urging member 64 has an elastic force in a direction in which the end portion 641 and the end portion 642 approach each other. Therefore, the end portion 641 of the urging member 64 that is locked to the rotation member side protrusion 635 urges the rotation member 63 in the clockwise direction. Accordingly, the external teeth 621 receive a force f1 from the external teeth 633 of the rotating member 63. As a result, the output shaft 5 is biased in the reverse direction.

  On the other hand, as shown in FIG. 4B, when the output shaft 5 rotates in the reverse direction from the reference position so that the point d1 on the output shaft 5 is away from the straight line L, the rotating member 63 Rotate clockwise about the axis. When the rotating member 63 rotates in the clockwise direction, the end portion 641 of the biasing member 64 is locked to the housing side protruding portion 25, and the end portion 642 is locked to the rotating member side protruding portion 635. . Even in this state, the urging member 64 has an elastic force in a direction in which the end portion 641 and the end portion 642 approach each other. Therefore, the end 642 of the urging member 64 that is locked to the rotation member side protrusion 635 urges the rotation member 63 in the counterclockwise direction. Accordingly, the external teeth 621 receive a force f2 from the external teeth 633 of the rotating member 63. As a result, the output shaft 5 is urged in the forward direction.

  As described above, when the output shaft 5 is in a position rotated in the forward direction from the reference position, the end member 642 is locked to the housing side protruding portion 25 and the end portion 641 is a rotating member. Locked by the side protrusion 635, the output shaft 5 is urged in the reverse direction via the rotating member 63. On the other hand, when the output shaft 5 is in a position rotated in the direction opposite to the reference position, the urging member 64 is engaged with the housing-side projecting portion 25 and the end 642 is projected on the rotating member side. Locked by the portion 635, the output shaft 5 is urged in the forward direction via the rotating member 63.

  In the present embodiment, as shown in FIG. 1, a shift position sensor 7 is provided in the vicinity of the rotating member 63. The shift position sensor 7 includes a sensor cover 71, a fixing member 72, a permanent magnet 73, and the like. The shift position sensor 7 is a non-contact rotation angle sensor that detects a relative rotation angle between the rotation member 63 and the fixed member 72 in a non-contact manner.

  The sensor cover 71 is attached to the front housing 21 on the side opposite to the rear housing 22 so as to cover the rotating member 63. The fixing member 72 is formed in a substantially cylindrical shape. One end of the fixing member 72 is positioned inside the cylindrical portion 631 of the rotating member 63, and the other end is fixed to the sensor cover 71. That is, the fixing member 72 is fixed to the front housing 21 via the sensor cover 71.

  The permanent magnet 73 is attached to the inner wall of the cylindrical portion 631 of the rotating member 63. Inside the fixing member 72, a magnetic detection element (for example, Hall IC) (not shown) is provided. When the permanent magnet 73 is rotated by the rotation of the rotation member 63, the magnetic flux density applied to the magnetic detection element inside the fixed member 72 changes. The magnetic detection element outputs a voltage corresponding to a change in applied magnetic flux density to the ECU 11 through the connector 74. Thereby, ECU11 can detect the relative rotation angle of the rotation member 63 and the fixing member 72 (front housing 21) based on the voltage value output from the magnetic detection element. The detection of the shift range of the automatic transmission by the shift position sensor 7 and the ECU 11 will be described in detail later.

Next, attachment of the rotary actuator 10 to the shift range switching device 100 will be described with reference to FIG.
In the present embodiment, the rotary actuator 10 is attached to the shift range switching device 100 in a state where the position of the manual shaft 101 in the rotational direction is at a position corresponding to the N range of the automatic transmission. That is, when the rotary actuator 10 is attached to the shift range switching device 100, the stopper 107 of the leaf spring 106 meshes with the recess 153 corresponding to the N range of the automatic transmission among the recesses 151 to 154 of the detent plate 102. State. When the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 of the rotary actuator 10 is connected to the manual shaft 101 in the above state. Note that, before the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 is stationary at the above-described reference position by the action of the biasing means 6.

(Joining process)
When the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 and the manual shaft 101 are first coupled by spline fitting. Specifically, while aligning the spline teeth formed on the outer end wall of the manual shaft 101 with the spline groove 54 formed on the inner wall of the coupling hole 53 of the output shaft 5, the manual shaft 101 is moved to the output shaft 5. Insert into the coupling hole 53. As a result, the manual shaft 101 and the output shaft 5 are coupled by spline fitting. At this time, the output shaft 5 is coupled to the manual shaft 101 with a specific spline groove 54 corresponding to a specific spline tooth of the manual shaft 101.

  In this embodiment, the reference position of the output shaft 5 in a state where the rotary actuator 10 is attached to the shift range switching device 100 is set to each shift range (P range, R range, N range, D range) of the automatic transmission. Output so as to correspond to a substantially intermediate position between two adjacent specific positions (for example, a position corresponding to the R range and a position corresponding to the N range) among a plurality of positions of the corresponding manual shaft 101 in the rotation direction. A coupling position of the shaft 5 with respect to the manual shaft 101 (corresponding position between the spline groove 54 and the spline teeth) is set.

(Main body rotation process)
Subsequently, the main body (housing 2) of the rotary actuator 10 is rotated so as to match the mounting location of the shift range switching device 100. Specifically, after the output shaft 5 is coupled to the manual shaft 101 in the coupling step, the main body of the rotary actuator 10 is viewed from, for example, the arrow Y direction in FIG. 2 against the urging force of the urging means 6. Rotate clockwise. Thereby, the bolt hole (not shown) of the rotary actuator 10 and the bolt hole 130 formed in the outline of the shift range switching device 100 are matched.

(Fixing process)
Subsequently, the rotary actuator 10 is fixed to the shift range switching device 100 by passing a bolt through the bolt hole of the rotary actuator 10 and the bolt hole 130 of the shift range switching device 100. When the rotary actuator 10 is fixed to the shift range switching device 100, the output shaft 5 is in a position rotated from the reference position to the positive direction side with respect to the housing 2.
The rotary actuator 10 is attached to the shift range switching device 100 through the above steps.

Next, the rotation amount of the main body of the rotary actuator 10 in the main body rotation step will be described.
FIG. 5A shows the relationship between the rotation angle of the output shaft 5 and the urging force that the output shaft 5 receives from the urging means 6 with a solid line. The “reference position” shown in FIG. 5A corresponds to the position of the output shaft 5 in FIG. 3, that is, the position of the output shaft 5 when the point d1 on the output shaft 5 overlaps the straight line L.

  When the output shaft 5 is at a position rotated in the forward direction side relative to the reference position (see FIG. 4A), the output shaft 5 receives a biasing force toward the reverse direction side from the biasing means 6. The magnitude of the urging force at this time is shown on the “+” side of the vertical axis in FIG. On the other hand, when the output shaft 5 is at a position rotated in the opposite direction side from the reference position (see FIG. 4B), the output shaft 5 receives a biasing force toward the forward direction side from the biasing means 6. The magnitude of the urging force at this time is shown on the “−” side of the vertical axis in FIG.

  FIG. 5A shows that the urging force that the output shaft 5 receives from the urging means 6 is larger as the output shaft 5 is farther from the reference position. In addition, when the output shaft 5 is in the vicinity of the reference position, the urging force that the output shaft 5 receives from the urging means 6 is “0”. Therefore, before the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 is stationary at the reference position by the action of the biasing means 6.

  In the present embodiment, as described above, the reference position of the output shaft 5 in the state where the rotary actuator 10 is attached to the shift range switching device 100 is the rotational direction of the manual shaft 101 corresponding to the shift range of the automatic transmission. The coupling position of the output shaft 5 with respect to the manual shaft 101 is set so as to correspond to a substantially intermediate position between two specific positions (a position corresponding to the R range and a position corresponding to the N range). Therefore, the shift range (P range, R range, N range) of the automatic transmission corresponding to the reference position of the output shaft 5 and the rotation angle of the output shaft 5 in a state where the rotary actuator 10 is attached to the shift range switching device 100. , D range) as shown on the horizontal axis of FIG.

  As described above, in the present embodiment, the rotary actuator 10 is attached to the shift range switching device 100 in a state where the position of the manual shaft 101 in the rotational direction is at a position corresponding to the N range of the automatic transmission. Therefore, in the main body rotating step, it is necessary to rotate the rotary actuator 10 main body so that the position of the output shaft 5 in the rotation direction with respect to the rotary actuator 10 main body matches the position corresponding to the N range. The amount of rotation of the main body of the rotary actuator 10 at this time is equal to the amount of rotation when the output shaft 5 rotates from the reference position to the position corresponding to the N range (the length of the arrow r1 in FIG. 5A).

  Here, consider a case where a rotary actuator (comparative example) in which the output shaft is urged in one rotation direction is attached to the shift range switching device. FIG. 5B shows the relationship between the rotation angle of the output shaft of the rotary actuator of the comparative example and the urging force received by the output shaft with a one-dot chain line. Before the rotary actuator of the comparative example is attached to the shift range switching device, the output shaft is stationary in a state where it is fully rotated in one direction. The position (stationary position) of the output shaft at this time is shown on the horizontal axis of FIG. Further, the shift range (P range, R range, N range, D range) of the automatic transmission corresponding to the rotation angle of the output shaft in a state where the rotary actuator of the comparative example is attached to the shift range switching device is shown in FIG. It is shown on the horizontal axis of 5 (B). When the rotary actuator of the comparative example is attached to the shift range switching device, the rotation amount of the rotary actuator main body in the main body rotation process is the rotation amount when the output shaft rotates from the stationary position to the position corresponding to the N range (FIG. 5). (Length of arrow r2 in (B)).

  The length of the arrow r1 described above is shorter than the length of the arrow r2. From this, it can be seen that the rotary actuator 10 of the present embodiment requires less amount of rotation of the main body in the main body rotation process than the rotary actuator of the comparative example. In the case of the rotary actuator of the comparative example, since the rotary actuator main body rotates in the main body rotation process, it is difficult or impossible to rotate the rotary actuator main body because the rotary actuator interferes with other surrounding members. There is a risk of becoming. On the other hand, in the case of the rotary actuator 10 according to the present embodiment, the amount of rotation of the main body of the rotary actuator 10 in the main body rotation process is small, so that interference with other members around the rotary actuator 10 is reduced.

Next, detection of the shift range of the automatic transmission by the shift position sensor 7 and the ECU 11 will be described.
As described above, the ECU 11 detects the relative rotation angle between the rotation member 63 and the fixed member 72 (housing 2) corresponding to the voltage value based on the voltage value output from the shift position sensor 7. be able to.
When the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 and the manual shaft 101 are coupled to each other, so that the rotating member 63 and the manual shaft 101 are interlocked via the output shaft 5. To do. Therefore, the rotation angle of the rotation member 63 corresponds to the rotation angle of the manual shaft 101.

  In this embodiment, after the rotary actuator 10 is attached to the shift range switching device 100, learning for detecting the shift range of the automatic transmission is performed. Specifically, for example, the ECU 11 switches the shift range of the automatic transmission by the rotary actuator 10 in the order of P range, R range, N range, and D range. At this time (the detent plate 102 of the manual shaft 101) The correspondence between the shift range when the stopper 107 is engaged with any one of the recesses 151 to 154 and the value detected by the shift position sensor 7 (output voltage value: rotation angle of the rotation member 63) is stored in the storage means. To do. In this manner, the ECU 11 associates, that is, learns, the shift range and the rotation angle of the rotation member 63. Thereby, the ECU 11 refers to the value stored in the storage means at the time of learning, so that the shift range of the automatic transmission corresponding to the output voltage value when the output voltage value from the shift position sensor 7 is within a certain range. Can be determined. That is, the ECU 11 can detect the shift range of the automatic transmission (the position of the manual shaft 101 in the rotation direction) based on the rotation angle of the rotation member 63 detected by the shift position sensor 7.

FIG. 6 shows the relationship between the rotation angle of the manual shaft 101 and the voltage output from the shift position sensor 7.
In the present embodiment, when the output shaft 5 is at the reference position, the urging force applied from the urging member 64 to the output shaft 5 is “0”. Therefore, at this time, backlash occurs in the rotational direction between the rotating member 63 and the output shaft 5 and between the output shaft 5 and the manual shaft 101. Due to this play, when the manual shaft 101 is at a position corresponding to the vicinity of the reference position of the output shaft 5, the voltage output from the shift position sensor 7 becomes unstable. On the other hand, when the manual shaft 101 is in a position other than the position corresponding to the vicinity of the reference position of the output shaft 5, the backlash is packed by the biasing member 64, and thus the shift position sensor 7 outputs a stable voltage. Can be obtained.

  Assuming that the range of the rotation angle of the manual shaft 101 when the voltage output from the shift position sensor 7 becomes unstable is the “unstable range”, the “unstable range” is as shown in FIG. When this “unstable range” overlaps, for example, a range for determining the shift range of the automatic transmission (“range determination range”) in the rotation angle of the manual shaft 101, the shift range sensor 7 determines the shift range. An error may occur in detection.

  However, in this embodiment, as described above, the reference position of the output shaft 5 in the state where the rotary actuator 10 is attached to the shift range switching device 100 is the rotation of the manual shaft 101 corresponding to the shift range of the automatic transmission. The coupling position of the output shaft 5 with respect to the manual shaft 101 is set so as to correspond to a position approximately in the middle between two specific positions in the direction (a position corresponding to the R range and a position corresponding to the N range). Therefore, the “unstable range” is in the vicinity of a position approximately halfway between the “position corresponding to the R range” and the “position corresponding to the N range” of the manual shaft 101 and does not overlap the “range determination range” ( (See FIG. 6).

  As described above, in this embodiment, an “unstable range” occurs in the rotation direction of the manual shaft 101. However, by devising a coupling position between the output shaft 5 and the manual shaft 101, the “unstable range” and the “range determination” are determined. The range does not overlap. Thereby, the above-described “learning for detecting the shift range of the automatic transmission” can be performed with high accuracy, and the shift range of the automatic transmission can be detected with high accuracy by the shift position sensor 7.

As described above, in the rotary actuator 10 according to the present embodiment, the urging means 6 urges the output shaft 5 in the reverse direction when the output shaft 5 is in the position rotated to the forward direction side from the reference position. To do. On the other hand, the urging means 6 urges the output shaft 5 in the forward direction when the output shaft 5 is at a position rotated in the direction opposite to the reference position.
Specifically, the urging means 6 includes a shaft member 61 that is fixed to the housing 2 on the outer side of the output shaft 5, and an outer tooth that is provided on an outer wall of the output shaft 5 in the radially outward direction and rotates together with the output shaft 5. A rotation member 63 having external teeth meshing with the member 62 and the external tooth member 62 and supported to be rotatable around the axis of the shaft member 5, and the rotation member 63 in the forward direction or the reverse direction in the rotation direction And an urging member 64 that can be urged. The housing 2 has a housing-side protruding portion 25 that protrudes in the axial direction of the shaft member 61. The rotation member 63 has a rotation member side protrusion 635 that protrudes in the axial direction of the shaft member 61. The urging member 64 is provided on the rotating member 63 such that the housing side protruding portion 25 and the rotating member side protruding portion 635 are sandwiched between the end portion 641 and the end portion 642.

  When the output shaft 5 is at a position rotated to the positive direction side from the reference position, the end member 642 is locked to the housing side protruding portion 25 and the end portion 641 is the rotating member side protruding portion 635. The output shaft 5 is urged in the reverse direction via the rotating member 63. On the other hand, when the output shaft 5 is in a position rotated in the direction opposite to the reference position, the urging member 64 is engaged with the housing-side projecting portion 25 and the end 642 is projected on the rotating member side. Locked by the portion 635, the output shaft 5 is urged in the forward direction via the rotating member 63. With this configuration, when the output shaft 5 is at a position different from the reference position, the output shaft 5 is always urged in the forward or reverse direction in the rotational direction by the urging means 6. Therefore, even if the output shaft 5 and the manual shaft 101 of the shift range switching device 100 are coupled with a predetermined play by spline fitting, the backlash in the rotational direction generated between the output shaft 5 and the manual shaft 101 is reduced. Can do. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator 10.

  In the present embodiment, the reference position of the output shaft 5 is set to the manual position corresponding to each shift range of the automatic transmission when the output shaft 5 is attached to the shift range switching device 100 in a state where the output shaft 5 is coupled to the manual shaft 101. It corresponds between two specific positions adjacent to each other among a plurality of positions in the rotation direction of the shaft 101. Therefore, in a state where the rotary actuator 10 is attached to the shift range switching device 100, the output shaft 5 is positively rotated in the rotational direction by the biasing means 6 regardless of the shift range corresponding to the manual shaft 101. It is always urged in the direction or the reverse direction. Thereby, in the state where the manual shaft 101 is in a position corresponding to each shift range of the automatic transmission, it is possible to close the backlash in the rotational direction generated between the output shaft 5 and the manual shaft 101. As a result, a shift between each shift range of the automatic transmission and the rotation angle of the output shaft 5 that should correspond to each of the shift ranges can be suppressed. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator 10.

  In the present embodiment, for example, if any one of the two adjacent positions is set as the position of the manual shaft 101 when the rotary actuator 10 is attached to the shift range switching device 100, the output shaft When the rotary actuator 10 in which 5 is stationary at the reference position is attached to the shift range switching device 100, after connecting the output shaft 5 to the manual shaft 101, the main body of the rotary actuator 10 is urged by the urging means 6. It is possible to match with the mounting location of the shift range switching device 100 only by rotating it slightly. As a result, even when another member or a protruding portion from the shift range switching device 100 is positioned around the rotary actuator 10, the main body of the rotary actuator 10 can be connected to the other member or the protruding portion when rotating at the time of attachment. Interference with is reduced. Therefore, attachment of the rotary actuator 10 to the shift range switching device 100 is facilitated.

  In the present embodiment, the rotary actuator 10 can detect the shift range of the automatic transmission by detecting the relative rotation angle between the rotation member 63 and the fixed member 72 fixed to the housing 2. A shift position sensor 7 is provided. The shift position sensor 7 can detect the rotational direction position of the manual shaft 101 corresponding to the rotational angle, that is, the shift range of the automatic transmission, by detecting the rotational angle of the rotational member 63. In the present embodiment, the urging member 6 can urge the output shaft 5 in the forward direction or the reverse direction in the rotational direction via the rotating member 63. Thereby, in addition to the play between the output shaft 5 and the manual shaft 101, the play between the rotating member 63 and the output shaft 5 can also be reduced. Therefore, an error between the detection value detected by the shift position sensor 7 and the actual shift range can be reduced. As a result, the shift range of the automatic transmission can be detected with high accuracy by the shift position sensor 7. Therefore, it is possible to switch the shift range with high accuracy by the rotary actuator 10.

  In the present embodiment, the urging means 6 is located outside the diameter of the output shaft 5. Therefore, for example, an increase in the size of the rotary actuator in the axial direction can be suppressed as compared with the case where the urging means is arranged on the axial direction side of the output shaft. Further, since the shift position sensor 7 is provided in the vicinity of the urging means 6, for example, compared with the case where the shift position sensor is arranged on the axial direction side of the output shaft, the axial size of the rotary actuator is increased, Or deterioration of mountability of a rotary actuator can be controlled.

(Other embodiments)
In another embodiment of the present invention, the rotating member is not provided, and the output shaft is biased in the reverse direction when, for example, the output shaft is in a position rotated more forward than the reference position in the axial direction of the output shaft. Then, when the output shaft is at a position rotated in the opposite direction side relative to the reference position, an urging means for urging the output shaft in the forward direction may be provided. Even with such a configuration, the backlash generated between the output shaft and the manual shaft can be reduced, so that the same effect as in the above-described embodiment can be obtained.

  In another embodiment of the present invention, instead of the biasing member described above, a member having elasticity such as rubber or a coil spring may be provided, and the housing and the rotating member may be connected by the member. Good. Even with such a configuration, the output shaft can be urged in the forward direction or the reverse direction in the rotation direction, so that the same effect as in the above-described embodiment can be obtained.

In another embodiment of the present invention, the shift position sensor may not be provided.
In the above-described embodiment, the example in which the output shaft of the rotary actuator and the manual shaft of the shift range switching device are coupled by spline fitting has been described. In another embodiment of the present invention, the cross-sectional shape of the coupling hole of the output shaft and the cross-sectional shape of the end portion on the insertion side of the manual shaft are formed in a non-circular shape (for example, square, D-shaped, etc.) May be combined.

  Thus, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the scope of the invention.

  2: housing, 3: electric motor, 5: output shaft, 6: biasing means, 10: rotary actuator, 100: shift range switching device, 101: manual shaft

Claims (6)

A rotary actuator that rotationally drives a manual shaft of a shift range switching device that switches a shift range of an automatic transmission,
An electric motor,
A housing for housing the electric motor;
An output shaft that is rotatably supported by the housing and can be coupled to the manual shaft to transmit a rotational output of the electric motor to the manual shaft;
Urging means capable of urging the output shaft in the forward direction or the reverse direction in the rotation direction,
When a predetermined position in the rotation direction of the output shaft with respect to the housing is a reference position,
The biasing means is
When the output shaft is at a position rotated to the forward direction side from the reference position, the output shaft is biased in the reverse direction,
A rotary actuator that biases the output shaft in a forward direction when the output shaft is at a position rotated in the reverse direction side with respect to the reference position.   The reference position is a plurality of positions in the rotation direction of the manual shaft corresponding to each shift range of the automatic transmission when the output shaft is attached to the shift range switching device with the output shaft coupled to the manual shaft. The rotary actuator according to claim 1, wherein the rotary actuator corresponds to a position between two adjacent positions. The biasing means includes a shaft member that is fixed to the housing outside the diameter of the output shaft, an outer tooth member that is provided on an outer wall in the radially outer direction of the output shaft, and rotates together with the output shaft; A rotating member having external teeth meshing with the member and supported so as to be rotatable about an axis of the shaft member, and a biasing member capable of biasing the rotating member in the forward direction or the reverse direction in the rotational direction And consist of
The rotary actuator according to claim 1, wherein the biasing member is capable of biasing the output shaft in a forward direction or a reverse direction in a rotational direction via the rotating member. The housing has a housing side protrusion that protrudes in the axial direction of the shaft member,
The rotating member has a rotating member side protrusion that protrudes in the axial direction of the shaft member,
The biasing member is
Provided on the rotating member so as to sandwich the housing side protruding portion and the rotating member side protruding portion between one end and the other end,
When the output shaft is in a position rotated to the positive direction side from the reference position, one end or the other end is locked to the housing side protruding portion, and the other end of the one end or the other end protrudes to the rotating member side. The output shaft is biased in the reverse direction via the rotating member,
When the output shaft is at a position rotated to the opposite side of the reference position, one end or the other end is locked to the housing side protruding portion, and one end or the other end protrudes to the rotating member side. The rotary actuator according to claim 3, wherein the rotary actuator is locked to a portion and urges the output shaft in a forward direction via the rotating member.   A shift position sensor capable of detecting a shift range of the automatic transmission by detecting a relative rotation angle between the rotation member and a fixed member fixed to the housing. Item 5. The rotary actuator according to Item 3 or 4.   The rotary actuator according to any one of claims 1 to 5, wherein the output shaft can be coupled to the manual shaft by spline fitting.

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